01/21/2011 07:03 pm ET | Updated May 25, 2011

Students Graded on Their Body Mass Index: a Scale as Arbitrary as Some Value-Added Teacher Scores

In a world of high-stakes measures, this one really takes the cake.

Until this week, an elementary school in Elmhurst, Illinois, has been using students' Body Mass Index (BMI) measurements as part of their physical fitness grades. The BMI is an individual's body weight divided by the square of his or her height.

According to the Chicago Tribune, the BMI measurement is taken from the fourth through the 12th grade. The BMI score, which is measured in the fall and again in the spring to see if there has been any improvement, is sent home with the students along with their progress report.

In other words, they're using the BMI as a value-added (or, in this case, poundage-added) accountability measure. Very cutting-edge!

However, the school was persuaded to stop the practice after serious questions were raised about the BMI test:

  • Unreliable results: One parent complained that her tall, slim son who plays hockey four times a week received a BMI score that indicated he was at risk of obesity.
  • Assessment-maker recommendations not followed: The company that designed the health and fitness assessment which uses the BMI recommends against using it as part of a child's progress report.
  • Misused test results: "The current research does not support the use of BMI data for grading purposes," Connie Chester, the school district's curriculum coordinator, told the Tribune.

According to Wikipedia, the BMI itself has become controversial. Many people, including physicians, have come to rely on its apparent numerical authority for medical diagnosis, but that was never the BMI's purpose. It is meant to be used as a simple method of classifying sedentary individuals with an average body composition.

In addition, BMI "standards" vary greatly from country to country, making global comparisons problematic. In 1998, the U.S. National Institutes of Health brought U.S. definitions into line with the World Health Organization guidelines, which had the effect of redefining approximately 25 million Americans previously considered "healthy" to "overweight." Similarly, some Asian standards also need adjustment. For example, the BMI cut-off figures in Singapore were revised in 2005 with an emphasis on health risks instead of weight.

Now, we'd really be getting somewhere if we could just get schools and districts to stop using standardized tests -- which have ALL THE SAME PROBLEMS -- for such high-stakes purposes as student promotion, retention and graduation and teacher evaluation.